Calling out the press is not entirely unheard of. Obama scolded reporters for doing things he didn't approve of; Nixon obsessed about the hostile liberal press. What's different is how happy Trump is to personalize his battles. Un-presidential? Yes. Unpopular? I suspect not. Media has to accept attitudes towards journalism have shifted according to partisan bias, and there are a lot of conservatives who disbelieve unfavorable reporting of Trump simply because they don't trust its source.

How did President-elect Trump handle press conference? Nailed it (CNN)